Bug#520072: net-tools: ifconfig eth0:1 up <ip> netmask <netmask> does not work first time

[Martín Ferrari]

Hi,

On Tue, Mar 17, 2009 at 04:35, Mark Poks <markpoks at wp.pl> wrote:

> typing in console for example:
>  ifconfig eth0:1 up 192.168.1.60 netmask 255.255.255.0
> and it fails with return message:
>  SIOCSIFFLAGS: Cannot assign requested address
> but when typing same command again, it works.

This is a weird condition, but anyway the core of the problem is what
you're doing. Let's see:

I can reproduce this when doing (I use the dummy interface, which get
cleaned when I do an rmmod)

# rmmod dummy; ifconfig dummy0:1 up 10.0.2.1/16
SIOCSIFFLAGS: Cannot assign requested address

If I change the order, this doesn't happen:

# rmmod dummy; ifconfig dummy0:1 10.0.2.1/16 up

It doesn't happen if I don't use the aliased interface, which gets us
closer to the real problem.

# rmmod dummy; ifconfig dummy0 up 10.0.2.1/16

If I forget about the address, I see the problem is with the "up" command:

# rmmod dummy; ifconfig dummy0:1 up
SIOCSIFFLAGS: Cannot assign requested address

Why you get this unhelpul error, I dont know. But the thing is that
you cannot "up" an aliased interface, because the up/down state is for
the whole interface. The aliases are just secondary addresses with an
associated name, but they don't behave like an interface at all, it's
an ugly hack and you will get better results handling addresses with
the "ip" command from iproute package.



-- 
Martín Ferrari